Drogue parachute
A drogue parachute is a parachute designed to be deployed from a rapidly moving object. It is often used to gain control of very fast descents, including those of spacecraft during reentry, or nuclear bombs such as the B61 and B83. (See also drogue.)
A drogue parachute is more elongated and far thinner than a conventional parachute, and thus provides less drag. This means that a drogue parachute cannot slow an object as much as a conventional parachute, but it can be deployed at speeds at which conventional parachutes would be torn apart.
Also, the drogue parachute's simpler design allows for easier deployment. Where a conventional parachute could get caught in itself while unfolding and fail to inflate properly (thus not slowing the falling object as much as it should), the drogue parachute will inflate more easily and more reliably generate the expected amount of drag.
Drogue parachutes are sometimes used to deploy a main or reserve parachute by using the drag generated by the drogue to pull the main parachute out of its container. The most familiar drogue parachute is the one used in this manner in parachuting. Such a drogue is referred to as a pilot chute when used in a single user(sports) parachute system. The pilot chute is only used to deploy the main or reserve parachute; it is not used for slowing down or for stability. Tandem systems are different; to reduce the terminal velocity of the pair of tandem jumpers, a drogue is deployed shortly after exiting the aircraft. It is later used to deploy the main parachute as on sports systems.
Drogue parachutes may also be used to help stabilize direction of something in flight, such as a thrown RKG-3 anti-tank grenade.
